The ability to monitor the balance between oxygen supply and demand, and to assess the impact of medical and surgical interventions on this balance, is of vital importance to the patient and the caregiver. Non-invasive methods (e.g., physical exam, pulse oximetry), and invasive methods (e.g., blood gas analysis, oximetric catheters) are currently employed to assess venous and/or arterial oxygen saturation. For example the pulmonary artery catheter (PAC) requires insertion via a central (e.g., jugular or subclavian) vein, and advancement through the patient's heart chambers to place the catheter tip into the pulmonary artery. Although the PAC provides valuable information regarding the patient's oxygen and cardiac status, it's placement and maintenance is invasive, requires special training to insert, and is fraught with risks, safety issues and adverse events including vascular perforation, infection, occlusion and bleeding. The central venous pressure catheter (CVP) is also placed in a large vein in the neck, chest, or groin and directed to a major venous structure near the heart. Both PAC and CVP catheters require anticoagulant and saline flushing to keep fluid lines open.
Accordingly, minimally invasive methods and systems for the measurement of venous and arterial oxygen saturation in the blood of blood-filled anatomical structures are needed.